dematrify               package:labdsv               R Documentation

_C_r_e_a_t_e _T_h_r_e_e _C_o_l_u_m_n _D_a_t_a_b_a_s_e _F_o_r_m _D_a_t_a _F_r_a_m_e _f_r_o_m _S_p_a_r_s_e _D_a_t_a _F_r_a_m_e_s

_D_e_s_c_r_i_p_t_i_o_n:

     Takes a sparse matrix data frame (typical of ecological abundance
     data) and converts it into three column database format.

_U_s_a_g_e:

     dematrify(taxa, filename, sep = ",", thresh = 0)

_A_r_g_u_m_e_n_t_s:

    taxa: a sparse data.frame or matrix, with samples as rows and taxa 
          as columns

filename: the name of the filename to produce

     sep: the separator to use in separating columns

  thresh: the minimum abundance to be included in the output

_D_e_t_a_i_l_s:

     The routine is pure R code to convert data from sparse matrix form
     to three column database form for export or reduced storage

_V_a_l_u_e:

     a data.frame with the first column the sample ID, the second
     column the taxon ID, and the third column the abundance.

_N_o_t_e:

     Typically, large ecological data sets are characterized by sparse
     matrices of taxon abundance in samples with many zeros in the
     matrix.   Because these datasets may be many columns wide, they
     are difficult to work with in text editors or spreadsheets, and
     require excessive amount of space for storage.  The reduced three
     column form is suitable for input to databases, and more easily
     edited.

_A_u_t_h_o_r(_s):

     David W. Roberts droberts@montana.edu

_R_e_f_e_r_e_n_c_e_s:

     <URL: http://ecology.montana.msu.edu/labdsv/R/labdsv>

_S_e_e _A_l_s_o:

     'matrify'

_E_x_a_m_p_l_e_s:

        library(labdsv)
        data(bryceveg)
        x <- dematrify(bryceveg)

